This invention relates to automatic clinical analyzers for chemistry measurement. In particular, the invention relates to a system of removing gas or bubbles from fluid which is used in such instruments.
Different automatic clinical chemistry analyzers are known, each having different desirable attributes and advantages. One analyzer uses a plurality of individual analysis modules having open reaction cups. Automatic samples probes withdraw sample volume from samples carried on a carousel and distributes the sample volume to analysis modules in accordance with selected tests. In another analyzer, the sample fluids are directed into a flow cell together with a diluent. Electrolytes in the fluid are determined in the flow cell.
In the various analyzers different fluids react with the sample fluid in the reaction cups. In a flow cell, it is necessary to have an alkaline buffer pass through a zone of the flow cell behind a gas permeable member in a manner which is substantially bubble-free so that a CO.sub.2 measurement can be accurately determined.
Different systems are known for removing the bubbles from alkaline buffer agents to permit CO.sub.2 measurement through a permeable membrane. The known systems are relatively complex and require multiple pumps to ensure effective operation with a minimum of downtime. Also, difficulties arise with regard to purging air, gas or bubbles from the system at start-up.
The present invention seeks to overcome the drawbacks with existing systems for debubbling or removing gas or air from liquid.